8 Of Simplt Earths. or combined fimply with fixed air, unmixed, it lcarcely ever occurs; when pure, it is perfe&ly white: its Ipecific gravity is about 2,3. It requires about 7900 times its weight of water to duiolve it in the temperature of 6o°. it is conibmable with all acids; with the nitrous and manne it forms falts that difficultlv cryitalhze, and are deliquefcent. If to a faturate ioluuon of thele falts the virriolic acid be added, though it takes rhe magnefia from the above- named acids, yet it forms no precipitate, as it does when it feizes the calcareous, barytic, or broi tifh earths, in the fame circumftances. The lalt, formed of the vitriolic acid and magnefia is alio very foluble in water; whereas the falts formed o! >his acid and the preceding earths’ are yery d.fikultly foluble; the former is bitter! the latter are infipid, or nearly fo. M.gnefia, in its pure ftate, is not as eafily duiolved as when combined with fixed air* 100 parts of it require for their foiution 104 of the vitnohc llandard acid, 286 of the nitrous, and 215,8 of the marine. And 100 parts of the vitriolic ftandard acid take up 5 : ,54 of pure magnefia; 100 parts of the nitrous acid 34,96 ; and 100 parts of the marine 46,34. This earth, expofed to the ftrongeft beat, will neither bum to lime nor melt; it is fufed by the fame fluxes as lime and mild calx, and with the fame appearances. ln its ulual fiate of drynefs mild magnefia is capable of taking up 1 times its weicht of water without letting out any drop; but, if expofed to the open a.r, it iuffers it to evaporate, hough more flowly than calcareous earth does, Eartb